High-Voltage Conductor Cover Fenders to Prevent Pin Flashover
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Solution Overview
Problem
Existing dielectric covers for high voltage components are prone to flashovers due to conductive liquids entering holes and creating a low resistance path between the components and ground, often caused by bird droppings or atmospheric moisture.
Innovation Solution
The addition of arched fenders over the holes in the dielectric cover to shield the retaining pins, increasing the dielectric surface length and preventing contamination, along with modified retaining pins featuring concentric skirts or ribs to block liquid runoff and enhance insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If holes are provided in the dielectric cover for retaining pins, then the cover can be securely attached to the insulator, but conductive liquids can enter the holes and create low resistance paths causing flashovers
Solution Approach 1:
A retaining pin with an intermediate insulating section is introduced between the conductive cover and the hole. This intermediate section acts as a mediator that prevents direct electrical contact between the cover and the hole, blocking the conductive liquid path while still allowing mechanical attachment through the hole.
2Ease of manufacture
If the dielectric cover is made simple in design, then manufacturing is easier and cost is reduced, but it lacks protection against conductive liquid contamination
Solution Approach 1:
The retaining pin is segmented into three distinct sections: a head section for manipulation, an intermediate insulating section for electrical isolation, and a shaft section for mechanical retention. This segmentation allows each part to perform its specific function while maintaining overall simplicity in the cover design.
3Strength
If retaining pins extend through the cover holes, then the cover is securely retained, but the pins become exposed to bird droppings and atmospheric moisture causing flashovers
Solution Approach 1:
The intermediate insulating section creates an electrically inert environment within the hole by preventing conductive liquid from reaching the pin. This inert barrier protects the pin from environmental contamination effects by blocking the conductive path that would otherwise allow moisture and bird droppings to cause flashovers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents flashovers by blocking conductive liquids and maintaining the dielectric properties of the pins, reducing the risk of electrical arcs and outages.
Implementation Method 1
Arched fenders are added over the insulator cover's holes (for retaining pins) to act as roofs or shields. The fenders may extend out from the cover by about one inch or more to shield the holes and pins.
Implementation Method 2
The fenders have multiple purposes. The fenders effectively prevent birds roosting on the ring of the pins (whose bodies are directly below the HV conductor), increase the dielectric surface length between the top of the cover and the electrical conductor above the pins
Implementation Method 3
The fenders have multiple purposes. The fenders effectively prevent birds roosting on the ring of the pins (whose bodies are directly below the HV conductor), increase the dielectric surface length between the top of the cover and the electrical conductor above the pins, and protect the pins from contamination issues which would reduce the dielectric properties of the pins.
Implementation Method 4
The pins have a ring (at least partially shielded by the fenders) at the end to allow the lineman to grasp the ring by a hot stick for insertion and removal of the pins.
Data Source
AI summary
A dielectric cover for an insulator, supporting a high voltage conductor in an electrical distribution system, has holes for receiving retaining pins. The retaining pins are used to secure the cover over the insulator and conductor. Arched fenders, which may be circular or have a bottom opening, extend out from the cover and overlie the holes and ends of the pins. The fenders prevent birds roosting on the pin, increase the dielectric surface length between the top of the cover and the electrical conductor above the pins, and protect the pins from contamination issues which would reduce the dielectric properties of the pins. Contamination issues include birds defecating on the pins, which can create a conductive path between the bird and the inside of the cover, and atmospheric moisture such as rain, snow, and ice on the pins. Thus, wildlife is protected from electrocution.